Parent just means "a lot" and is using 90% to convey their opinion. The actual numbers are closer to 0.083%[1][2][3][4] and parent thinks they should be 0.01-0.1% of the total build cost.

1. Assuming 500,000 USD in permitting costs. See 2.

2. Permits and approvals: Building permits, environmental assessments, and utility connection fees add extra expenses. In some jurisdictions, the approval process alone costs hundreds of thousands of dollars. https://www.truelook.com/blog/data-center-construction-costs

3. Assuming a 60MW facility at $10M/MW. See 4.

4. As a general rule, it costs between $600 to $1,100 per gross square foot or $7 million to $12 million per megawatt of commissioned IT load to build a data center. Therefore, if a 700,000-square foot, 60-megawatt data center were to be built in Northern Virginia, the world’s largest data center market, it would cost between $420 million and $770 million to construct the facility, including its powered shell and equipping the building with the appropriate electrical systems and HVAC components. https://dgtlinfra.com/how-much-does-it-cost-to-build-a-data-...

> Source? I can't immediately find anything like that

I’ve financed two data centers. Most of my time was spent over permitting. If I tracked it minute by minute, it may be 70 to 95%. But broadly speaking, if I had to be told about it before it was solved, it was (a) a real nuisance and (b) not technical.